Given:
μ = 2 min, population mean
σ = 0.5 min, population standard deviation
We want to find P(x>3).
Calculate the z-score
z= (x-μ)/σ = (3-2)/0.5 = 2
From standard tables, obtain
P(x ≤ 3) = P(z ≤ 2) = 0.9772
Therefore
P(x > 3) = P(z > 2) = 1 - 0.9772 = 0.0228
Answer: 0.02275
